The present invention relates generally to a tube plug seal having an improved tear line pattern.
Automotive transmissions are often filled with transmission fluid before they are shipped to an automobile assembly plant. To retain the fluid in the transmission during shipment, tube plug seals are press fit into fluid connection ports located in the housing of the transmission. Each tube plug seal typically includes a plurality of linear, tear lines which extend radially from a center point of the seal and which define a plurality of triangular-shaped flaps. The tear lines are weakened portions in the seal formed by reducing the thickness of the tube plug seal material. After installation of the transmission into the automobile, a mating tube is pushed through the tube plug seal thereby tearing the seal material along the tear lines and creating a passageway for fluid flow. In addition to plugging the fluid connection port prior to tearing, the tube plug seal must also provide a secure seal for the joint between the mating tube and the fluid connection port after the seal is torn.
Current tube plug seals have several shortcomings. Tube plug seals having a conventional tear line design may tear radially outward from the center point of the seal beyond the defined tear line, thus preventing the tube plug seal from acting as a secure seal between the mating tube and the fluid connection port. Further, the amount of force required to tear a conventional tube plug seal along its tear lines varies with temperature. Finally, insertion of the mating tube causes a high stress upon the seal along the circumference of the fluid connection port. The high stress may cause the seal to tear not only radially along the defined tear lines but also circumferentially along the circumference of the fluid connection port thereby detaching pieces of seal material from the plug. The detached pieces may then flow into the transmission causing contamination.